Patent GB-888002-A (GB)
Title: Improvements in and relating to light display apparatus, e.g., signal apparatus
IPC: G08G1/095
Filed: 1957-03-20
Abstract: 888,002. Toys. WINSTANLEY, J. E. March 20, 1958 [March 20, 1957], No. 8844/58. Divided out of 888,001. Class 132(3) [Also in Groups XI, XX, XXX and XXXVIII] Apparatus for displaying and mixing of coloured lights for use in road or railway signalling comprises a mixing chamber containing sources of light of different colours, e.g. red, green, the inner surface of the walls of the chamber being of a light diffusing character to mix the lights by diffusion and multiple reflection within the chamber so as to produce an additive colour, e.g. amber, when two or more lights are operative simultaneously, and means for transmitting the individual light or the additive colour only to one or more light outlets so arranged that the light sources cannot be viewed directly. A shielded path including a reflector may be provided to transmit the light from the mixing chamber to an outlet. The reflector and path may be formed by a one-piece light transmitting solid body having an opaque outer coating under which a white coating may be provided. An apparatus for signalling or display may consist of a box-like base housing 1, Fig. 1, containing two electric lamps 2, 3 coloured red and green respectively and a transparent glass or synthetic resin column 4, the lower end of which within the housing 1 has bevelled faces 5, 6 opposite the lamps and a 45 degrees facet at the upper end fitted with a vizor 8. The column 4 is coated with a white covering outside which is a black covering. The coverings may be painted on or applied as sheathings. In a modification, the casing 10, Fig. 8, has the lower part formed as a diffusing chamber 1b and housing the lamps 2a, 3a below an aperture 11 above which is a block of glass or plastic having a bevelled lower end 5a, 6a and a reflecting face at the upper end for directing the light to a lens 9. More than two lamps of different colours may be used e.g. red, green and blueviolet, the intensity of each being controlled by an adjustable aperture or other means. The signalling apparatus may be combined with a railway system in such a way that the overload in the circuit to the signals when both electric lmaps are lighted is accompanied by a reduction in track current to slow down a train. Fig. 10 shows an arrangement for a junction signal of a model railway in which the green signal G of the set line is in series with the red signal R of the non-set line. During the change-over, the switch for the signal control temporarily completes the circuit through both contact members c, c<SP>1</SP> so that for each signal both lamps are lit and an amber light appears at both signals. The lamps are fed from the secondary winding s<SP>1</SP> of a transformer so that when both lamps of both signals are lit the increased load will cause a lowering of the propulsion-current voltage supplied by the secondary winding s<SP>2</SP> to the track so that train movement is slowed down. As a safeguard against a failure, each lamp may be duplicated. The switching of the lights may be effected automatically such as by a timing control. A similar effect may be obtained at a section of the track controlled by one signal.